SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d45708821330eec60a221fdb75a26ff34a1ea3ea8847afcd2be8509fedae56' 
  AND token = 'qmrsXIal1yUidU6ynG749MoXwz8IBzo5Yk3BZxPH4Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}